This invention relates to the field of socket devices used for mounting integrated circuit packages and will have special but not limited application to accommodating those integrated circuit packages having leads or contact pads in a closely spaced relationship.
Socket devices have been used for several years in the mounting of integrated circuit packages for burn-in and similar testing purposes as well as production or commercial uses when applied to a printed circuit board. Examples of some such sockets can be found in U.S. Pat. Nos. 4,623,208; 4,533,192; 4,498,047 and 4,491,377. As miniaturization of IC packages have progressively occurred over the years, the lead spacing has progressively decreased. The same can be said with respect to the spacing between pads of a leadless integrated circuit package. Such fine pitch leaded and leadless packages generally cannot be accommodated by the usual socket devices having single rank contacts due to the necessity of making the contacts so thin in order to make engagement with the IC leads or pads that one must sacrifice the ability to accurately control the contact pressure of the contacts. For example, there are gull wing type integrated circuit packages having leads on 25 mil (0.025 inch) centers. Therefore to provide and construct a socket having contacts to accommodate such 25 mil centered leads, the contacts at the points of engagement with the IC leads must be very thin. In the following described invention, the contacts of the socket device at the point of engagement with the IC leads have a width of 12 mils. The arrangement and alignment of the contacts are so designed so as to provide sufficient width in order to control the engagement or contact force of the contact with the IC lead.